With “Dory,” Pixar has crafted a sequel to one of its biggest hits, a movie that is still one of the studio’s highest-grossing films more than 10 years later. (Only “Inside Out” and “Toy Story 3” have made more domestically than “Nemo.”)

What made the fishy film such a big hit when it was released in the summer of 2003?

Release date certainly helped. “Finding Nemo,” “Inside Out,” and “Toy Story 3” were all released in the summer, a time of year when parents are no doubt looking for an all-ages feature. It’s not until you get to the sixth-highest-grossing Pixar movie, “The Incredibles,” that you find one that didn’t open during the warmer months.

Against a backdrop of action-filled movies, a Pixar movie can stand out as something different. “Inside” proved to be a steady performer during the summer, even coming in at number one during the competitive July 4 weekend.

Media analyst Paul Dergarabedian told Variety at the time that newer movies like “Terminator: Genisys” found it difficult going against “Inside” and “Jurassic World.”

"Those two holdover films are tough to open against because they are still drawing all demographics,” he explained.

Critical acclaim also contributed to the success of “Nemo,” which later won the Oscar for Best Animated Movie. As Gregory M. Lamb wrote at the time for The Christian Science Monitor, " 'Finding Nemo' is going to make a big splash with young children. And parents or grandparents who dive in with them are likely to have a great time, too… [an] animated delight."